No, I don't have a reason [1]
I was walking down the street
No, I don't have a reason
Towards your house

Look, you can see it now—that nostalgic scenery
the crescent moon suspended in the night [2]

Where's the sun, where's the sun
that we used to be able to see back then
Where's the sun, where's the sun
that set for good over there [3]

"Whatever's fine"
Even though I want to think that
No matter what I do
Nothing ever works out for me and

I'll never ever get used
to being cold in the dark, to you not being there

Where's the sun, where's the sun?
that was smiling down on us back then
Where's the sun, where's the sun?
If you were here now I could probably show you the kindness you deserve [4]

Where's the sun, where's the sun?
that we used to be able to see back then
Where's the sun, where's the sun?
that set for good over there

Where's the sun, where's the sun?
that was smiling down on us back then
Has the world stopped turning?
Where's the sun?

Notes:

[1] I angsted about how to best express the なんて here. Alternatives included "No particular reason" (which felt too glib) and "There's no point" (which felt too different).

[2] I didn't really get the image here. In English the moon would not "sway" I don't think. I considered going with "floating" cuz that seems poetically natural, but I dunno, I like suspended. "in the night" I added because it needed somewhere to be suspended.

[3] This "over there" is pretty wishy-washy, but it's what they said and I kept it mainly because it parallels the "back then." Some vague "other" time and place. I think that seems valid. My alt would have been "on that horizon."

[4] This line I basically rewrote based on how I read it. The literal translation is something like, "If it were now, [subject omitted] should be able to do it kindly [or "make it kind/nice/friendly"]. So yeah, I read this as him feeling guilty for their break-up, and that if it were the him of today (who is more mature), he could have done it right [by being nicer to her].